In January this year, Beijing launched a 14-month nationwide campaign against unauthorised internet connections, including VPN services, saying all service providers must obtain government approval.
Nathan Freitas, a fellow at Harvard's Berkman Centre for Internet and Society, said "anyone who was anyone" in China depended on "the VPN of the week that works" to access essential blocked resources.
Any new restrictions would cause "significant" harm to global collaborations, including Chinese academics or open-source projects on the mainland, he said.
"There is this idea that for people inside – the playing field, the collaboration field, was levelled because they had VPNs," he said.
John Zhang, a chemistry professor at New York University Shanghai, has used his college's VPN network to access academic information for years. If that changed, "the impact on my work would be serious", Zhang said.
Another Chinese academic at a university in Shanghai said he had used VPNs since 2012 to access sites such as Google, a service he needed to "accurately and quickly" find academic papers.
He now bypasses the firewall with his university's VPN system. Since researchers could still access legal VPNs through work, he did not think the restrictions were harmful to China's academia – "at least for now".
A Chinese physics professor at a university in Beijing said he hoped the VPN crackdown would not affect his ability to use Google.
"Baidu has absolutely no use for my work," he said, referring to the Chinese search engine.
"It is a shame ... Without Google, academic research and study will definitely be adversely affected."
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Academics in China are reluctant to publicly comment on censorship. But both Chinese and foreign researchers in the country need to tap into to global conversations for "well-informed research", according to Dr Nicole Talmacs, lecturer in media and communications at Xian Jiaotong-Liverpool University.
One former visiting scholar at Fudan University in Shanghai tried multiple services in his "adventures of finding a VPN". The first was blocked upon arrival, the second worked for one night and the third worked only after a prolonged configuration process.
He said it was "catastrophic" for his research to be restricted from file sharing services such as Dropbox or Google Drive. "I don't want to risk my access being limited to whatever the government decides I can use," he said.
Dr Christopher Balding, a business and economics professor at the HSBC Business School in Shenzhen, frequently accesses Twitter, Gmail, and Google Scholar for his work.
"If we start taking [VPNs] away, it's going to be very problematic," Balding said.
"When you're going to such extremes, you're stopping basic access to information for professors ... It's really going to harm the types of jobs and industries that China says it wants to grow."
Dr Mario Poceski, a former visiting scholar at Fudan University in Shanghai, said the lack of complete internet access was a constant hassle while he was in China, creating conditions that were "rather intolerable".
He added that this would negatively affect the country's appeal for foreign scholars.
The firewall's impact on research was raised when the legislature met in March in Beijing.
Even Liu Binjie, a former director of the General Administration of Press and Publication, indicated support at the National People's Congress meeting this year for the reintroduction of Google Scholar to China after the authorities suspended access to the service in 2010.
Luo Fuhe, a vice-chairman of the Chinese People's Political Consultative Conference, also said this year that limited access to the internet was harmful to scientists.
"It is not normal when quite a number of researchers have to buy software that helps them bypass the country's firewalls in order to complete their scientific research," Luo said.
The communist government has been increasing efforts to maintain its ideological grip on the country's universities, which President Xi Jinping has vowed to turn into "strongholds of the party's leadership".
Universities – which fall under the control of Communist Party committees – have repeatedly been told to maintain purity in their socialist ideology, including steering clear of teaching topics such as press freedom and civil rights.
The party dispatched anti-graft teams earlier this year to inspect 29 top universities on criteria including the implementation of the party's guiding principles for education and strong "political awareness".
China's drive for internet restrictions on academics may stem from a desire to keep data on Chinese internet platforms and sensitive information such as defence or cybersecurity research within its borders, according to Freitas.
But when scholars and researchers could not use VPNs to access a free and open internet, it might lead to government censorship of academic information and a "brain drain" of skilled individuals overseas, he noted. "Intelligent people want to be connected with a global cohort of collaborators," he said.
Balding said China was "definitely a different environment" from when he arrived in the country eight years ago, citing its restrictive internet and politically sensitive academic environment.
Asked if he was now considering working outside China, he replied soberly: "I should probably start thinking about looking."